FEDERALISE
federate, federalize, federalise
(verb) unite on a federal basis or band together as a league; “The country was federated after the civil war”
federate, federalize, federalise
(verb) enter into a league for a common purpose; “The republics federated to become the Soviet Union”
federalize, federalise
(verb) put under the control and authority of a federal government
Source: WordNet® 3.1
Etymology
Verb
federalise (third-person singular simple present federalises, present participle federalising, simple past and past participle federalised)
Alternative spelling of federalize
Source: Wiktionary